大深度地下连续墙施工对周边环境变形的影响

Effect on Environmental Deformation Due to Deep Diaphragm Construction

课题依托杭州中心城区在建大型工程开展大深度地下连续墙施工影响实时跟踪监测,研究施工对土体变形的影响效应。项目基坑最深超过31m,在杭州尚属首例,极具研究的典型意义和价值。数据分析结果表明:在开挖卸荷作用下,施工时土体向槽内变形呈较强规律特征,浅部土层受成槽施工影响较大;浇筑混凝土后,土体侧向变形几乎未有向槽外回复趋势,很可能与土层性质与槽壁加固密切相关;由于成槽机械作用及测斜管所处位置影响,地下连续墙两侧土体侧移规律差异较大;施工时槽侧土体侧移随槽距增加逐渐衰减,但成槽施工影响范围较大,必须引起充分重视。

In the paper, real-time tracing monitoring of deep diaphragm construction is implemented on the basis of large construction-in-process in the city center of Hangzhou, which aims at studying effect on soil deformation due to diaphragm construction. The extreme depth of foundation pit of project is more than 31m, which is first case in Hangzhou and has typical value of srudy. The study indicates that ：the variation of lateral deformation of soil caused by diaphragm construction toward inner side of groove presents strong regularity under unloading effect, and the superficial soil layer suffers bigger effect caused by diaphragm construction than subjacent soil layer; there is little reverse trend of lateral deformation of soil toward outward side of trench, as likely as not the factors that the properties of soil and trench consolidation play a part; the principles of soil deformation are different between two sides of the trench of diaphragm due to the effect of trench cutter and the location of inclinometer tube ; The value of lateral displacement decreases with the increase of distance from the trench, however, the incidence of diaphragm is large, which should be fully paid attention to.